Identification card

ABSTRACT

An identification card is prepared by attaching an antenna and integrated circuit chip onto a core layer of polyolefin, attaching a bottom sheet to the core layer thus encasing the antenna and integrated circuit chip, providing an image-receiving layer on one or both outer surfaces of the resulting sandwich, and laminating a protective layer or layers over the image-receiving layer(s). The identification document displays improved durability, ease of manufacture and protection of the electronic components.

BACKGROUND OF THE INVENTION

[0001] This invention relates to an improved identification card. Morespecifically, this invention relates to an identification cardcontaining an internal antenna and integrated circuit chip laminatedbetween two protective, non-rigid layers onto which artwork may beprinted, which are then laminated between to rigid outer layers.

[0002] “Smart cards” which contain an IC chip are well known in the artand typically have been used for credit card and ATM transactions. Smartcards may either have contacts on their surface to interface with a cardreader or they may be contactless cards and incorporate an antennawithin the body of the card to transfer data without physical contactwith a reading device.

[0003] Typically smart cards have been made with a rigid core onto whichan IC chip and antenna are positioned by means of glue or a mechanicaldevice. The rigid core is then covered with a plastic, encasing thestructure in a polymer. For example, U.S. Pat. No. 5,809,633 issued toMundigl, et al. discloses a method whereby an antenna is inserted into arecess in a carrier body. U.S. Pat. No. 5,955,021 issued to Tiffany, IIIteaches the use of low shrinkage glue to secure the electroniccomponents to a rigid plastic core layer, which is then placed into abottom mold assembly. A top mold assembly is then attached to the bottommold creating a void. Thermoplastic is then injected into the void spaceto secure the electronic components. Similarly, U.S. Pat. No. 6,049,463issued to O'Malley, et al. discloses a microelectric assembly includingan antenna embedded within a polymeric card by means of a mold assembly.The antenna and chip are placed into a mold and polymeric material isinjected into the mold thus encasing the components.

[0004] U.S. Pat. No. 6,036,099 issued to Leighton discloses a processfor manufacturing a combination contact/contactless smart card via alamination process utilizing core sheets made from polyvinyl chloride(PVC), polyester, or acrylonitrile-butadiene-styrene (ABS). In theLeighton method, a region of the card is milled to expose the contactsof the card.

[0005] Due to the rigidity of the components used in the prior artcards, the electronic components cards can be subject to damage frombending stresses. Also, securing the antenna and chip with glue or amechanical means is complicated and can needlessly increase the costs ofproduction. Understandably, processes utilizing molds involve increasedcosts of tooling and production not seen in a lamination process. Boththe highly plasticized poly(vinyl chloride) type and thepolyester/poly(vinyl chloride) composite type can become brittle overtime because of migration of the plasticizers, thus reducing theresistance of the document to cracking; such cracking renders the cardunusable and vulnerable to tampering. Data that are crucial to theidentification of the bearer are often covertly repeated on the documentin encrypted form for data verification in a magnetic stripe, bar code,radio frequency module or integrated circuit chip. The inability toretrieve such data due to cracking renders the document invalid. Inaddition, many of the polyester/poly(vinyl chloride) composite documentshave exhibited extreme sensitivity to combinations of heat and humidity,as evidenced by delaminating and curling of the document structure.

[0006] Therefore, a need exists for a low-cost, easily constructedidentification card having an antenna and chip incorporated into thebody of the card, which protects these electronic components fromdamage. Applicants' invention relates to a unique structure capable ofprotecting the IC chip and antenna. Applicants' invention contains tworelatively shock-absorbing layers, which may contain indicia. In anembodiment, two rigid outer laminate layers encase the relativelyshock-absorbing layers, adding structural support and protection.Applicants' card differs from the prior art in that normally rigidmaterials are used throughout the card, thus permitting externalstresses and bending to damage the delicate IC chip and antenna. Inapplicants' improved design, rigid outer layers disseminate externalforces over a broad area of compliant layers, thus protecting theelectronic components.

SUMMARY OF THE INVENTION

[0007] Accordingly, this invention provides an identification cardcomprising:

[0008] a core layer comprising a silica-filled polyolefin, said corelayer having a first side and a second side,

[0009] at least one antenna fixed to said to said first side of saidcore layer,

[0010] at least one computer chip electrically connected to saidantenna,

[0011] a bottom sheet comprising a silica-filled polyolefin attached tosaid first side of said core by a first adhesive layer such that saidantenna and said chip are enveloped between said core and said bottomsheet.

[0012] an akyld resin spid containing an anti-binding agent printed onsaid first side of said core layer,

[0013] a first laminate layer attached to said second side of said corelayer by a second adhesive layer,

[0014] a second laminate layer attached to said bottom sheet by a thirdadhesive layer such that said core and said bottom sheet are encasedbetween said first laminate layer and said second laminate layer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 of the attached drawings shows a cross-section of anidentification card of the present invention.

[0016]FIG. 2 of the attached drawings shows a cross-section of analternative embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0017] To prepare an identification card of the present invention thefirst step is preshrinking a core layer. In order to provide anidentification document having a bright white background and good colorrendition, it is generally preferred that the core layer be formed froman opaque sheet of printable silica-filled polyolefin, such as thematerials sold commercially by PPG Industries, Inc., Pittsburgh, Pa.under the Registered Trade Mark “TESLIN” sheet.

[0018] The first indicium or indicia, which are typically the invariantinformation common to a large number of identification documents, forexample the name and logo of the organization issuing the documents, maybe formed by any known process capable of forming the indicium on thespecific core material used. However, since it is usually desired toprovide numerous copies of the first indicium on a large area of corelayer material (in the form of a large sheet or web) in order to allowthe preparation of a large number of “blank” documents at one time, aprinting process such as color laser printing, is normally used to applythe first indicium. A modified laser printer useful for forming thefirst indicium in the present process is described in U.S. Pat. No.5,579,694.

[0019] In order to minimize the risk of damage to the fragile electroniccomponents, preferably alkyd resin spids containing an anti-bindingagent are printed onto one side of the shrunken core sheet on the sideopposite from the indicia. These spids may be printed in any pattern,however, in an embodiment they are printed onto the core in a“racetrack” or oval pattern. Antennae, typically silver-epoxy antennae,are then printed onto the spids in a matching pattern. Integratedcircuit chips are attached to solder bumps on the antennae in theconventional manner.

[0020] The core layer with attached antennae and IC chips is then bondedto a bottom sheet of printable, silica-filled polyolefin with anadhesive layer. The adhesive layer may be composed of a number ofcommercially available adhesives, however, very desirably it is composedof a co-polyester based adhesive such as the adhesive sold commerciallyby Transilwrap, Inc., Richmond, Ind. under the name Transilwrap® TXP(3).Because IC chips are typically much thicker than the antennae,preferably recesses are cut in the TXP(3) adhesive layer to accommodatethe IC chips. By removing a section of the adhesive, the identificationcard will be of uniform thickness. Because recesses were cut in thisTXP(3) adhesive layer, in order to bond the IC chip to the bottom layer,an additional layer of adhesive is required. Although this adhesive maycomprise any suitable adhesive, in the preferred embodiment it is acarboxylated polyethylene hot melt adhesive such as that manufactured byTransilwrap, Inc. and sold under the name Transilwrap® KRTY. Thisadhesive is applied to the bottom layer prior to assembly of the cardand serves to bind the IC chip to the bottom layer. During lamination ofthe identification card, the TXP(3) adhesive layer will flow freely thusadhering the core sheet with the bottom sheet, sandwiching theelectronic components in a bonded, flexible laminate of silica-filledpolyolefin.

[0021] Two layers of substantially transparent polymer are affixed tothe bonded core layer/bottom layer structure. Depending upon thematerial used for the core layer and bottom layer, the process used toproduce the first indicium and the type of substantially transparentpolymer employed, fixation of the polymer layers to the core layer maybe effected by heat and pressure alone. However, it is generallypreferred to provide an adhesive layer on each polymer layer to improveits adhesion to the core layer. This adhesive layer may be a polyester,polyester urethane, polyether urethane or polyolefin hot melt orultraviolet or thermally cured adhesive, and the adhesive may be coated,cast or extruded on to one surface of the polymer sheet. The polymerlayers themselves may be formed from any polymer having sufficienttransparency, for example polyester, polycarbonate; polystyrene,cellulose ester, polyolefin, polysulfone, or polyimide. Either anamorphous or biaxially oriented polymer may be used. Two specificpreferred polyesters for use in the process of the present invention ispoly(ethylene terephthalate) (PET), which is readily availablecommercially, for example from ICI Americas Inc., Wilmington, Del. 19850under the Registered Trade Mark “MELINEX”, and poly(ethyleneterephthalate glycol) (PETG), which is readily available commerciallyfrom Eastman Kodak Chemical, Kingsport, Tenn. The polymer layers providemechanical strength to the image-receiving layer or layers and hence tothe image(s) in the finished document. The thickness of the polymerlayers is not critical, although it is generally preferred that thethickness of each polymer layer (including the thickness of itsassociated adhesive layer, if any) be at least about 0.1 mm, anddesirably is in the range of from about 0.125 to about 0.225 mm. Anyconventional lamination process may effect lamination of the polymerlayers to the core layer, and such processes are well known to thoseskilled in the production of identification documents.

[0022] The image-receiving layer of the present identification documentmay be formed of any material capable of receiving an image by dyedifflusion thermal transfer. However, very desirably the dye diffusionthermal transfer printing step of the present process is effected by theprocess of U.S. Pat. No. 5,334,573. This patent describes a receivingsheet or layer which is comprised of a polymer system of which at leastone polymer is capable of receiving image-forming materials from a donorsheet with the application of heat, the polymer system of the receivingsheet or layer being incompatible with the polymer of the donor sheet atthe receiving sheet/donor sheet interface so that there is no adhesionbetween the donor sheet and the receiving sheet or layer duringprinting. In addition, the polymer system of the receiving sheet orlayer can be substantially free from release agents, such assilicone-based oils, poly(organosiloxanes), fluorinated polymers,fluorine- or phosphate-containing surfactants, fatty acid surfactantsand waxes. The present process may employ any of the donorsheet/image-receiving layer combinations described in this patent.Suitable binder materials for the dyes, which are immiscible with thepolymer system of the image-receiving layer, include cellulose resins,cellulose acetate butyrate, vinyl resins such as poly(vinyl alcohol),poly(vinylpyrrolidone) poly(vinyl acetate), vinyl alcohol/vinyl butyratecopolymers and polyesters. Polymers which can be used in theimage-receiving layer and which are immiscible with the aforementioneddonor binders include polyester, polyacrylate, polycarbonate,poly(4-vinylpyridine), poly(vinyl acetate), polystyrene and itscopolymers, polyurethane, polyamide, poly(vinyl chloride),polyacrylonitrile, or a polymeric liquid crystal resin. The most commonimage-receiving layer polymers are polyester, polycaprolactone andpoly(vinyl chloride). Processes for forming such image-receiving layersare also described in detail in this patent; in most cases, thepolymer(s) used to form the image-receiving layer are dissolved in anorganic solvent, such as methyl ethyl ketone, dichloromethane orchloroform, and the resultant solution coated on to the polymer layerusing conventional coating apparatus, and the solvent evaporated to formthe image-receiving layer. However, if desired the image-receiving layercan be applied to the polymer layer by extrusion casting, or by slot,gravure or other known coating methods.

[0023] The identification cards of the present invention may have only asingle image-receiving layer, but is generally preferred that they havetwo image-receiving layers, one such layer being provided on each layerof polyester on the side thereof remote from the core layer. Typically,one or more second indicia intended for human reading may be printed onthe image-receiving layer on the front side of the identificationdocument, and one or more additional second indicia intended for machinereading (for example, bar codes) may be printed on the image-receivinglayer on the back side.

[0024] Following the printing of the second indicia on theimage-receiving layer, a protective layer is affixed over at least theportion of the or each image-receiving layer carrying the secondindicia; this protective layer serves to protect the relatively fragileimage-receiving layer from damage, and also prevents bleeding of thethermal transfer dye from the image-receiving layer. Materials suitablefor forming such protective layers are known to those skilled in the artof dye diffusion thermal transfer printing and any of the conventionalmaterials may be used provided they have sufficient transparency andsufficient adhesion to the specific image-receiving layer with whichthey are in contact and block bleeding of dye from this layer.Typically, the protective layer will be a biaxially oriented polyesteror other optically clear durable plastic film.

[0025] The protective layer desirably provides additional securityfeatures for the identification card. For example, the protective layermay include a low cohesivity polymeric layer, an optically variable ink,an image printed in an ink which is readable in the infra-red orultraviolet but is invisible in normal white light, an image printed ina fluorescent or phosphorescent ink, or any other available securityfeature which protects the document against tampering or counterfeiting,and which does not compromise the ability of the protective layer toprotect the identification document against wear and the elements.

[0026] In an alternate embodiment, the image-receiving layer may beformed from any material capable of receiving ink-jet printing. Manycommercially available inkjet receiver coatings will suffice, however itis important that the inkjet receiver coating is only applied in thearea where printing will occur, to ensure that the polyester layer willproperly adhere to the core layer. The identification card may then bepersonalized with a common inkjet printer prior to addition of thepolyester layers. In this embodiment the personalized information isprinted between the core layer and the polyester layers, thuseliminating the need for an additional protective layer.

[0027]FIG. 1 of the accompanying drawings shows a schematiccross-section through an embodiment of an identification card of thepresent invention. The document comprises a core layer 12 and a bottomlayer 14, both formed of an opaque white reflective polyolefin(preferably the aforementioned TESLIN® sheet). One side of the corelayer and one side of the bottom sheet are printed with fixed indicia16. Sandwiched between the core layer 12 and the bottom layer 14 are anantenna 18 connected to an integrated circuit chip 20. An alkyd resinspid 22 lies beneath the core layer 12 and the antenna 18. An adhesivelayer 24 (preferably KRTY) is applied to the bottom layer 14 on the sidefacing the core layer 12. The bottom layer 14 and the core layer 12 arejoined with an adhesive layer 26 (preferably TXP(3)). Recesses 28 arecut into the adhesive layer 26 to accommodate the integrated circuitchip 20.

[0028] The core layer 12 and bottom layer 14 are sandwiched between twopolymer layers 30 formed from an amorphous or biaxially orientedpolyester or other optically clear plastic such as polycarbonate. Eachof these polymer layers 30 is fixedly secured to the core layer 12 andbottom layer 14 by an adhesive layer 32. On the opposed side of eachpolymer layer 30 from the laminated core layer 12 and bottom layer 14 isprovided an image-receiving layer 34 suited to accept a printed image orportrait or other variable indicia by dye diffusion thermal transfermethods.

[0029] After the variable indicia have been printed on theimage-receiving layers 34, a biaxially oriented polyester or otheroptically clear durable plastic protective layer 36 is applied toprotect the variable indicia and prevent bleeding of dye from theimage-receiving layers 34. The protective layer 36 may be provided witha low cohesivity layer, security ink or other security feature.

[0030]FIG. 2 of the accompanying drawings shows a schematiccross-section through an alternate embodiment of an identification cardof the present invention. The document, generally designated 10,comprises a core layer 12 and a bottom layer 14, both formed of anopaque white reflective polyolefin (preferably the aforementionedTESLIN® sheet). Opposed sides of the core layer and the bottom sheet areprinted with fixed indicia 16. Sandwiched between the core layer 12 andthe bottom layer 14 is an antenna 18 connected to an integrated circuitchip 20. An alkyd resin spid 22 lies beneath the core layer 12 and theantenna 18. An adhesive layer 24 (preferably KRTY) is applied to thebottom layer 14 on the side facing the core layer 12. The bottom layer14 and the core layer 12 are joined with an adhesive layer 26(preferably TXP(3)). Recesses 28 are cut into the adhesive layer 26 toaccommodate the integrated circuit chip 20.

[0031] The laminated core layer 12 and bottom layer 14 is sandwichedbetween two polymer layers 30 formed from an amorphous or biaxiallyoriented polyester or other optically clear plastic such aspolycarbonate. An inkjet receiver coating 38 is supplied between thecore layer 12 and a polymer layer 30. The inkjet receiver coating 38 maycontain personalized data 40 Each of the polymer layers 30 is fixedlysecured to the core layer 12 and bottom layer 14 by a layer 32 ofadhesive.

[0032] The following Examples are now given, though by way ofillustration only, to show details of specific preferred reagents,conditions and techniques used to prepare identification cards of thepresent invention.

EXAMPLE 1

[0033] Core layers of silica-filled polyolefin were prepared, preferablyof the aforementioned TESLIN®, of 0.01″ thickness in the size of four A4sheets (210 mm×297 mm×4 mm). The core layers were heated at 105° C. forapproximately 30 minutes to pre-shrink the material. Alkyd resin spids,in a racetrack design, were then printed on the bottom side of theshrunken core layers, and background artwork was printed on a side ofthe core layers. Silver-epoxy antennae were then screenprinted onto thespidded areas of the sheets, and IC chips were then attached to theantennae. Because the core layers were heated repeatedly during thisprocess, it is important that the polyloefin be pre-shrunk to avoid anyshrinking problems during printing of the artwork or attachment of theelectronic components.

[0034] Bottom layers were prepared by pre-shrinking 10 mm thicksilica-filled polyolefin sheet in the manner described above. Artworkwas printed onto a side of the bottom layer. 1.5 mm of an adhesive,preferably KRTY, was applied to an opposed side of the bottom layers toadhere the IC chip to the bottom layer.

[0035] The core layers and the bottom layers were joined by a free filmof adhesive (7 mm of TXP(3)) cut into A4 sized sheets. Holes were precutin the TXP(3) adhesive sheets to accommodate the IC chips. The corelayers and bottom layers were then joined by the TXP(3) adhesive layersuch that the antennae and chips were sandwiched between them, thusencasing and protecting the electronic components. The core layers andbottom layers were joined (up to 10 at a time) using a Tetrahedronpress. Initially, the pressure used was very low (of less thanapproximately 400 psi) and the temperature was relatively high(approximately 290° F.) so that the TXP(3) adhesive layer was allowed toflow and so that the electronic components are not damaged. Pressure andtemperature were then increased to approximately 3 ksi and 300° F. tobond the three layers together. The temperature was then lowered toapproximately 170° F. while the pressure remained relatively high(approximately 2 ksi) so that the TXP(3) adhesive layer would solidifywithout altering the form of the pressed core layer. Pressure was thenreduced and the press was opened, yielding a core layer/bottom layerlaminate encasing the electronic components.

[0036] This core layer/bottom layer was then laminated using a nip-rolllamination process. The top laminate material used was a 7/3 TXP(5)/KRTYonto which a dye diffusion thermal transfer receiver coating had beenapplied to the adhesive side. The bottom laminate was a 7/3 TXP (5)/KRTYlayer. The resulting card was then imprinted with personal informationon both the front and back using an Atlantek printer. Security features,such as UV sensitive inks or Polasecuree, can be added to the topsurface of the card. After this, a 0.001″ thick bi-axial polyesterlaminate was applied to both sides of the identification card.

EXAMPLE 2

[0037] The core layer/bottom layer was prepared as described inExample 1. For personalization, however, an inkjet receiver coating,preferably a Grace-Davision formulation, was patch-coated onto selectiveareas of the core layer opposite the bottom layer. It is important thatthe entire core layer was not coated with the receiver coating or thecore would not properly adhere to the polyester laminate. Image and textwere printed onto the receiving layer using a Canon® 8200 printer andpigment-based inks. The printed cores were then belt laminated on bothsides using 7/3 TXP (0)/KRTY as both the top and bottom laminate.

[0038] From the foregoing, it will be seen that the present inventionprovides an identification card which affords significant improvementsin durability (by protecting the integrated circuit chip and antenna)and ease of manufacture as compared with the prior art identificationcards and smart cards described above. It is to be understood that theabove-described embodiments are merely illustrative of the presentinvention and represent a limited number of the possible specificembodiments that can provide applications of the principles of theinvention. Numerous and varied other arrangements may be readily devisedin accordance with these principles by those skilled in the art withoutdeparting from the spirit and scope of the invention as claimed.

I claim:
 1. An improved identification card comprising: a core layercomprising a silica-filled polyolefin, said core layer having a firstside and a second side, at least one antenna affixed to said first sideof said core layer, at least one integrated circuit chip electricallyconnected to said antenna, a bottom sheet comprising a silica-filledpolyolefin attached to said first side of said core by a first adhesivelayer such that said antenna and said chip are encased between said corelayer and said bottom sheet.
 2. An improved identification cardaccording to claim 1 further comprising an akyld resin spid containingan anti-binding agent printed on said first side of said core layer andpositioned between said antenna and said first side of said core layer.3. An improved identification card according to claim 1 furthercomprising a first polymer layer attached to said second side of saidcore layer by a second adhesive layer.
 4. An improved identificationcard according to claim 3 further comprising a second polymer layerattached to a first side of said bottom sheet by a third adhesive layersuch that said core layer and said bottom sheet are enveloped betweensaid first polymer layer and said second polymer layer.
 5. An improvedidentification card according to claim 1 further comprising animage-receiving layer affixed to said second side of said core layer. 6.An improved identification card according to claim 1 further comprisinga second image-receiving layer affixed to said first side of said bottomsheet.
 7. An improved identification card according to claim 5 having atleast one indicium printed by dye diffusion thermal transfer on theimage-receiving layer, the identification card further comprising aprotective layer fixed to the image receiving layer and attached oversaid indicium.
 8. An improved identification card according to claim 5having at least one indicium printed by ink jet printing on theimage-receiving layer.
 9. An improved identification card according toclaim 2 wherein said alkyd resin spid is a polyester epoxy materialcontaining a release agent.
 10. An improved identification cardaccording to claim 2 wherein said alkyd resin spid is an acrylate epoxymaterial containing a release agent.
 11. An improved identification cardaccording to claim 2 wherein said alkyd resin spid is a vinyl acetateepoxy material containing a release agent.
 12. An improvedidentification card according to claim 3 wherein said first polymerlayer is a polyester or a polycarbonate.
 13. An improved identificationcard according to claim 4 wherein said second polymer layer is apolyester or a polycarbonate.